Silk-screen printing device



Dec. 10, 1963 1.. G. DUBUlT 3,113,510

SILK-SCREEN PRINTING DEVICE Filed March 8, 1962 Fig. I 9

Fig.2

3 mv-QACLEW" iw; fifaifml ML United States Patent 3,113,510 SILK-SCREEN PRINTING DEVMIE Louis Gilbert Duhuit, 60 Rue Vitrnve, Paris, France Filed Mar. 8, 1962, Ser. No. 178,432 (Jlaims priority, application France Dec. 18, 1061 1 Claim. (Cl. 101-124) The present invention relates to a device for printing on bodies of revolution with concurrent generator lines, by the silk-screen process.

Various types of machines are already known which permit printing to be carried out on objects having a completely or partially conical form, by using the so-called silk-screen process; in point of fact however, the machines concerned have been specially designed for such printing operation. These specialized machines are very expensive to manufacture. Some of them are however provided with a movable device permitting the printing in question to be made and which, when removed from the machine, make it possible to utilize the latter for printing on flat objects or objects of generally cylindrical shape.

It is known that in order to print on conical objects by the silk-screen process, it is necessary for the screen to pivot about the apex of the cone which encloses the object, whereas the squeegee placed parallel to the upper generator line of the cone is fixed and causes the ink to be passed through the screen.

However, both in the case of machines or movable devices, the solutions adopted up to the present time have led to the production of systems in which the screencarrier describes a circular trajectory about a centre which is either physical and adjustable in position so as to vary the radius of the said projectory, which has the result of making the system extremely bulky, or virtual, which then necessitates a rail or other circular guiding member having a determined radius which must be changed for any substantial departure from that radius.

The present invention has for its object to provide an extremely simple and readily removable device which enables printing to be effected on conical bodies or bodies of similar form, and which can be very readily adapted to all printing machines which employ the silk-screen process, comprising a screen-carrier trolley moving on straight rails and a squeegee-carrier which can be held in a fixed position.

The device forming the object of the invention consists essentially, on the one hand of a bracket which can be fitted on a fixed portion of the machine and which carries two pairs of grooved pulleys, the horizontal axes of which can be orientated so as to concur at a virtual centre located in front of the machine and determining the circular trajectory to be followed by the screen-carrier frame, and on the other hand of a rigid arcuate member capable of rolling between the two pairs of grooved pulleys and carrying two arms intended to support the frame of the silk-screen, the said arcuate member being given a circular to-and-fro motion by the screen-carrier trolley of the machine or by a member which drives the said trolley. The profile of the pulleys is such that substantially all vertical play of the arcuate member, and therefore of the screen, is eliminated.

The rigid arcuate member may be formed by a fiat strip of steel or rigid material, bent to a determined radius of curvature, a set of arcs of different radii being produced in this way, when so required.

The screen-carrier arc may be driven in a to-and-fro movement by the trolley which usually drives the screencarrier frame of the machine, through the intermediary of cables coupled on the one hand to the extremities of the said trolley and on the other to the opposite extremities of the arcuate member.

The screen-carrier arc may receive its motion by friction ,il3,5l Patented Dec. 10, 1963 of its outer face with a friction band fixed on the screen-carrier trolley of the machine, or by means of a toothed rack rigidly fixed to the said trolley and engaging with a curved rack fixed on the arcuate member.

The screen-carrier arc may receive its to-and-fro motion by means of a toothed rack which is rigidly fixed to it and which engages with a pinion driven by the mechanism of the machine.

Gne form of construction of the device is described below by way of example only and without implied limitation, reference being made to the accompanying drawings, in which:

FIG. 1 shows the device seen in side elevation;

FIG. 2 shows a plan view of the device;

FIG. 3 is a partial section, to a larger scale, taken along the line IH-III of FIG. 2.

The device according to the invention consists firstly of a bracket comprising for example two arms 1 and 1' (FIGS. 1 and 2), fixed on a horizontal cross-member 2 and adaptable by means of bolts or screws 3 to any member of the machine which is fixed in position in the lateral direction.

At the extremities of the cross-member 2 are arranged two pairs of grooved pulleys 6 and 6' provided with ball bearings 7 and 7' carried by shafts 8 and 8 fixed on small arms 9 and 9. The latter are mounted on the crossmember 2 by means of a bolt 10 which enables them to be directed on each side of the cross-member so as to cause their axes to converge at a virtual point 0 (FIG. 2) which constitutes the virtual centre of the trajectory which should be followed by the silk-screen with respect to the squeegee to satisfy the printing conditions imposed by the characteristics of the objects to be printed, and especially by their angle of conicity.

The device also comprises a rigid arcuate guide rail or similar member 11 bent into substantially part-cylindrical shape, the radius of curvature being a function of the position of the point 0. All objects having a radius of curvature between zero and the radius of the arcuate member could be printed by placing them at a judicious point located between the points 0 and P.

The said arcuate member 11 includes a concave and a convex vertical side face and horizontally extending top and bottom small faces upon which the said pulleys 6 and 6' roll. The two arms 12 firmly attached to said member 11 hold the silk screen frame 22 with the silk screen 23 which follows a circular trajectory about center point 0 when acting upon the conical surface of the rotational body 21 to be printed upon. This body 21 is rotatably held by and between a chuck 24 mounted in the tiltable support 25 and a center element 27 mounted in the tiltable support 23, both supports 25, 28 resting upon the machine frame 26.

In order to obtain this circular displacement of the arcuate member 11 between the pulleys 6 and 6', it is possible to establish a coupling between the said arcuate member and any member of the machine which has a to-and-fro movement.

In the example shown, the member chosen is the driving trolley of the screen-carrier described in United States Patent No. 3,090,300 of May 21, 1963.

In the machine described in the said patent, the squeegee-carrier bar 5 is carried by an articulated arm 4', on the one hand on an extension 13' of an arm 13 carried by horizontal shafts 1d and 14' and on the other hand on a coupling rod da pivoting about a shaft 16 parallel to the shaft 14', this assembly forming an articulated parallelogram permitting vertical movement of the squeegee. The trolley of the screen-carrier frame is constituted by arms 15 and 15 sliding on the rail 14' and on a further rail 16. These arms 15 and 15' are coupled together by a cross-member 17 on which there can be fixed other arms carrying a silk-screen frame for the other utilizations of the machine.

In the present case, the parts intended for these other uses are thus eliminated.

At the extremities of the cross-member 17 are fixed small plates 18 and 18' through which pass two cables 19 and 19, the other extremities of which are fixed to the opposite extremities 20 and 20' of the arcuate member 11.

The arms 15 and 15' and the cross-member 17 receive from the machine a to-and-fro movement, and it can thus be seen that the cables 19 and 19, driven in this same movement by the cross-member 17, apply their tractive pull alternately on the extremities of the arcuate member 11 and force the latter to roll between the pulleys 6 and 6'. The screen carried by the arms 12 thus describes the required circular motion.

The squeegee carried by the rod 5 remains fixed in the lateral direction with the arm 4', together with the arms 4 mounted on the shafts 14 and 16, and which carry the bracket 11'2.

It will be observed that the arcuate member 11 is only formed by a single flat strip and that it is easy in this way to construct a series of arcuate strips of different radii capable of satisfying all printing conditions.

In addition to the simplicity of conversion of the screencarrier system, and the ease with which the device can be fitted on any machine, it should be noted that the bringing into position and the removal of the objects are greatly facilitated by the arrangement of the screen completely in front of the machine and outside it.

It is obvious that the cable drive described by way of example can be replaced by a system of toothed racks engaging each other, one fixed t0 the trolley which moves with a to-and-fro motion, and the other fixed to the arcuate member 11. The rack fixed to the said arcuate member may engage with a pinion driven with an alternating movement of rotation by the machine.

The arcuate member 11 may further be driven by friction against a part of the trolley driven by the machine.

Finally, the device may be" given any modifications of form and detail which permit its adaptation to all the applications for which the device can be used, without departing from the scope of the invention.

What I claim is:

In a silk screen printing machine for printing upon substantially conical surfaces comprising a silk screen frame reciprocable in a substantially horizontal plane; supporting and actuating means for said frame comprising in combination a substantially flat guide rail bent into substantially part-cylindrical shape and having a concave and a convex side face and longitudinally extending top and bottom small faces; supporting means for said screen frame attached to the concave side face of the guide rail; a stationary bracket mounted opposite the convex side face of the guide rail; two swing members articulated in spaced relation to said bracket and extending therefrom in horizontal direction; a pair of opposing rollers rotatable on horizontal axes mounted on each of said swing members; each pair of said rollers engaging and firmly gripping the top and bottom small face of the guide rail; and actuating means for the guide rail for reciprocating the same between said pairs of rollers relative to the surface to be printed upon.

References Cited in the file of this patent UNITED STATES PATENTS 2,105,572 Williams Jan. 18, 1938 2,152,356 Meyer et al. Mar. 28, 1939 2,229,347 Shurley Jan. 21, 1941 2,301,119 Holbrook Nov. 3, 1942 2,444,574 Martin July 6, 1948 2,972,943 Velonis Feb. 28, 1961 

